Facebook Chief Product Officer Chris Cox and WhatsApp Vice President Chris Daniels are leaving

  • Chris Cox, Facebook's chief of product, is leaving the company, CEO Mark Zuckerberg announced on Thursday.

  • Cox is the latest in a string of key Facebook executive departures over the past year. 

Facebook FB Chief of Product Chris Cox is leaving the tech company, CEO Mark Zuckerberg announced in a note on Thursday.

"Chris and I have worked closely together to build our products for more than a decade and I will always appreciate his deep empathy for the people using our services and the uplifting spirit he brings to everything he does," Zuckerberg wrote.

Cox was one of Facebook's first 15 engineers and climbed his way up the company. He oversaw a huge part of the company, and he was a part of the so-called M-Team, which is a group of key executives that Zuckerberg relies on. 

Cox worked on a number of key Facebook products, including News Feed, he ran the Facebook app, and most recently, he oversaw the strategy for all of Facebook's apps, Zuckerberg wrote.

Cox informed the company of his decision to resign on Monday, according to a Facebook financial filing .

"As Mark has outlined, we are turning a new page in our product direction, focused on an encrypted, interoperable, messaging network," Cox wrote in a goodbye post on his Facebook profile. "This will be a big project and we will need leaders who are excited to see the new direction through."

Other organization changes

Along with Cox, Zuckerberg announced that WhatsApp Vice President Chris Daniels is also leaving the company. Daniels was the head of the WhatsApp messaging app since last May, when he took over after the departure of WhatsApp Co-founder Jan Koum. Daniels previously ran the company's business development team and its Internet.org effort.

"Chris is one of the clearest and most principled business thinkers I've met and the diversity of challenges he has helped us navigate is impressive," Zuckerberg wrote.

Will Cathcart will replace Daniels as the new head of WhatsApp, Zuckerberg said. Cathcart previously ran the Facebook app, Zuckerberg said.

"Will is one of the most talented leaders at our company -- always focused on solving the most important problems for people and clear-eyed about the challenges and tradeoffs we face," Zuckerberg wrote.

The company will also elevate Fidji Simo to head of the Facebook app, succeeding Cathcart in that role, Zuckerberg said. Simo has previously lead the company's work on video and advertising for the Facebook app, Zuckerberg said.

"She is one of our most talented product and organizational leaders -- passionate about building community and supporting creativity, and focused on building strong teams and developing future leaders," Zuckerberg wrote.